The present invention relates to cement compositions and, more particularly, in certain embodiments, to amine phosphono retarder compositions for retarding Sorel cements and associated methods.
Cement compositions may be used in a variety of subterranean applications. For example, in subterranean well construction, a pipe string (e.g., casing, liners, expandable tubulars, etc.) may be run into a well bore and cemented in place. The process of cementing the pipe string in place is commonly referred to as “primary cementing.” In a typical primary cementing method, a cement composition may be pumped into an annulus between the walls of the well bore and the exterior surface of the pipe string disposed therein. The cement composition may set in the annular space, thereby forming an annular sheath of hardened, substantially impermeable cement (i.e., a cement sheath) that may support and position the pipe string in the well bore and may bond the exterior surface of the pipe string to the subterranean formation. Among other things, the cement sheath surrounding the pipe string functions to prevent the migration of fluids in the annulus, as well as protecting the pipe string from corrosion. Cement compositions also may be used in remedial cementing methods, for example, to seal cracks or holes in pipe strings or cement sheaths, to seal highly permeable formation zones or fractures, to place a cement plug, and the like. One type of cement composition is a Sorel cement composition.
These subterranean applications operations generally occur under a wide variety of well bore conditions, for example, ranging from shallow wells (less than about 1,000 feet) to extremely deep wells (greater than about 35,000 feet). Generally, the cement composition should remain in a pumpable state until the cement composition has been placed into the desired location. To retard the set time of Portland cement compositions, set retarder compositions have been included therein. As used herein, the phrase set retarder compositions refers to a wide variety of compositions commonly used in cementing operations for delaying the set time of a cement composition, including lignosulfates, hydroxycarboxy acids, phosphonic acid derivatives, synthetic polymers (e.g., copolymers of 2-acrylamido-2-methylpropane sulfonic acid (“AMPS”)), borate salts, and combinations thereof.
Because of the difference in chemistry between Sorel cements and Portland cement, set retarder compositions suitable for use in Portland cements may not perform as desired in Sorel cements. For example, certain types of these set retarder compositions do not perform well with Sorel cements at high temperatures. Furthermore, Sorel cements are generally more susceptible to high temperatures than Portland cement compositions. Thus the use of Sorel cements is often limited to subterranean applications with temperatures not exceeding of 240° F.